1. Field of the Invention
The present invention relates an accounting system comprising a computer and an insertion device for receiving and printing on account cards.
In microcomputers oriented for accounting purposes, there is the need to record the data on an account card provided with a magnetic track. The use of these cards causes difficulties during the various operations on the same card since the positioning thereof at a given line shows differences of alignment. These differences of positioning are due to the fact that, the card being made of thin card material and being very wide, a considerable clearance is required between its width and that of the guides. In the end, this clearance is manifested in difficulty of operation on the magnetic track, inasmuch as there is the possibility of a reading error due to the angular displacement of the card. 2. Description of the Prior Art
In a known arrangement, after recording the information on the magnetic carrier, it is read and compared (the exclusive-OR operation is performed), character by character, with the original message stored in a buffer. If a difference is found between any two characters, an error signal is emitted and invalidates the card.
This arrangement has the drawback of declaring cards which are still valid as invalid solely because of the detection of an error during the sequence of verification after the recording operation; moreover, if the operator wishes to assure himself of the actual invalidity of the card, he must command other reading cycles manually. The problem, therefore, exists of having available a more efficient arrangement for determining whether a card is actually invalid before declaring it such.